This application claims the priority of Korean Patent Application No. 2002-70064 filed on Nov. 12, 2002, in the Korean Intellectual Property Office, the disclosure of which is incorporated herein in its entirety by reference.
1. Field of the Invention
The present invention relates to an actuator and a micro-drive apparatus including the actuator, and more particularly, to a slim actuator improved for use in mobile micro-drive apparatuses and a slim micro-drive apparatus comprising the slim actuator.
2. Description of the Related Art
FIG. 1A is a plan view of a conventional actuator 10 included in an existing IBM micro-drive apparatus, and FIG. 12 is a side cross-section of the conventional actuator 10 taken along line A-N. Referring to FIGS. 1A and 1B, the conventional actuator 10 is mainly comprised of a plurality of head gimbal assemblies 11a and 11b and a coil assembly 13 installed between the head gimbal assemblies 11a and 11b. The end, that is, a fantail molding portion, of the coil assembly 13 is molded with a voice coil 15. A head 17 is mounted on the right sides of the head gimbal assemblies 11a and 11b. The number of head gimbal assemblies depends on the number of mounted disks. The voice coil 15 forms a magnetic assembly, together with a magnet (not shown) installed on a base plate (not shown) under the actuator 10 so as to be opposite to the voice coil 15. The actuator 10 is rotated by an electromagnetic force created by the interaction between an electrical field generated by current flowing in the voice coil 15 and the magnetic field of the magnet, thereby moving the head 17 to a desired track on a disk.
FIG. 2 is an exploded perspective view of the component elements of the conventional actuator 10 shown in FIGS. 1A and 1B. Referring to FIG. 2, the coil assembly 13 molded with the voice coil 15 is interposed between the first and second gimbal assemblies 11a and 11b. A pivot bearing 12 is inserted into a hole 16a of the first head gimbal assembly 11a, a hole 16b of the coil assembly 13, and a hole 16c of the second head gimbal assembly 11b in sequence and combined by a retainer nut 14, thereby competing the conventional actuator 10. Here, the pivot bearing 12 acts as the center around which the actuator 10 rotates.
Referring to FIGS. 1B and 2, the entire size of the conventional actuator 10 is increased due to the coil assembly 13 separately installed between the first and second head gimbal assemblies 11a and 11b, and according to this, a disk drive adopting the conventional actuator 10 becomes thicker.
Currently, most current mobile micro-drive apparatuses have a CompactFlash type I (CF-I) form which provides a thickness of 3.3 mm, and their application range is gradually extending. On the other hand, conventional IBM micro-drive apparatuses are excellent in terms of capacity, unit cost per storage capacity, and future competitiveness but adopt a CF-II form which provides a thickness of 5.0 mm because they cannot become slim due to the above-described actuator structure. Conventional CF-II actuators maximize a resonance characteristic, which is one of structure vibration characteristics, by positioning the coil assembly 13 between two channels, that is, between the first and second head gimbal assemblies 11a and 11b as shown in FIG. 2. However, such an arrangement is not suitable for a slim CF-I actuator using a single channel. In particular, there is not enough space in which to combine a fantail molding portion because of the thickness of a uni-mount portion of a suspension. Thus, the demand of conventional IBM disk drive apparatuses have a limited demand because they cannot become ultra-slim and light for use in mobile disk drives.